Centrifugal separator



April 4, 1950 Filed Jan. 8, 1946 T. v. HANNO 2,502,945

CENTRIFUGAL SEPARATOR 3 Sheets-Sheet 1 h mn 70,

April 4, 1950 I T. v. HAN NO CENTRIFUGAL SEPARATOR '5 Sheets-Sheet 2 Filed Jan. 8, 1946 W pfi W WWW E WV E Z I r 2 mi f,

T. V. HANNO CENTRIFUGAL SEPARATOR April 4, 1950 5 Sheets-Sheet 3 Filed Jan. 8, 1946 INVENTOR TORE VERNER HANNO BY V Mow ATTO NEYS Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE GENTRIFUGAL SEPARATOR Application January s, 1946,, Serial No. 639,732 In Sweden January 22, 1945 '4 Claims.

For the removal of yeast cells, remaining after the fermentation, from beer, centrifugal separators are now employed. The yeast cells, which are heavier than the beer, deposit under the influence'of the centrifugal force in the sludge space of the centrifugal bowl. and are maintained there till the centrifuge has been stopped. Thus beer freed from yeast cells is discharged through the outlet of the centrifuge. For the separation of the yeast cells there are generally used hermetically closed centrifuges, but so-called paring disc centrifuges could also be used.

After the centrifuge is stopped it is usually flushed clean by connecting its inlet to a water supply pipe and feeding water through it. At the same time an outlet, provided in the pipe line between the outlet of the centrifuge and the storage tank to which the beer liberated from yeast is conducted from the centrifuge, is opened. Because the centrifugal bowl is not then rotating this known method involves the risk that such yeast cells, which have deposited in the sludge s-paceof the bowl and are carriedaway with the flush water flow, may enter and remain in the discharge pipe line. When the centrifuge is next time used for treating beer these yeast cells may be carried into the storing tank for beer. As yeast cells must not be present in the finished beer the described procedure is open to serious objections.

Of course it is possible, by continuing the flushing for a very long time, e. g., for some'hours, to achieve a more or less complete clean-flushing, in that the flush water removes no more yeast cells from the bowl, either because all the sludge mass containing yeast cells has been flushed out or because no more yeast cells are torn off by the flush water. This involves, however, a great waste of water and the necessity of attending to the installation long after the centrifuge has been stopped.

According to the present invention it is insured that no yeast cells shall enter the storage tank. This is eifected'by-flowing the flush liquid backwards through the centrifuge. This is effected by connecting to the discharge pipe of the centrifuge an inlet for flush liquid, e. g. a common water supply pipe, and vbyproviding an outlet for flush liquid at the feed inlet of the centrifuge. The direction of flow being during 2 the whole period of flushing from the outlet to the inlet of the centrifuge, no yeast cells torn off in the bowl can be conveyed into the connecting pipe between the centrifuge and the storage tank.

Fig. l is a diagrammatic view of a centrifugal separator installation adapted for carrying out my improved process.

Fig. 2 is a vertical sectional view through the upper part of a separator equipped with-a paring disc and in which my improved process is adapted to be practiced, the separator being the same as the separator forming part of the installation shown in Fig. 1.

Fig.3 is a view similar to Fig. 1 but showing an installation having a separator of the aforementioned hermetically closed type, in place of a separator equipped with paring discs.

Referring first to Fig. 3:

Beer, containing yeast cells, is, by means of a centrifugal pump 2, carried from a tank I throughacentrifuge 3 to a storing tank or a socalled pressure tank 4 for beer freed from yeast cells. To the feed pipe 50. between the pump and the centrifuge is connected an outlet pipe 6. which is shut off during the separating operation; and to the connecting pipe 1 between the centrifuge 3 and the pressure tank 4 is connected an inlet pipe 8 for flush liquid, which is shut off during the separating operation. The pipe 8 is connected to a container for flush liquid (not shown) or to a water supply pipe.

Durin the centrifuging the beer streams from the tank I through the pump 2 and the pipe 5a into the centrifuge, and thence, after being freed from the yeast, through the pipe 1 into the tank 4. When the centrifuging is to be interrupted a .valve 9 in the pipe 5a and a valve I 0 in the pipe 1 are closed. A valve H in the pipe 8 and a valve I2 in the pipe 6 are opened, and the flush liquid streams then in the direction of the arrows through the pipe lines and the centrifuge. Any yeast cells which are detached in the centrifu l bowl thus pass through the feed pipe 511 insurance is absolute against entry of yeast cells into the pipe 1 during flushing.

In starting the centrifuge valves 9 and ID are closed and valves H and [2 are opened and water is led through the centrifuge backwards, e. g., in the direction of the arrows, until the centrifuge attains its full speed. Then the valve [2 is closed and the valve 9 opened and the flow of beer begun. After the water has been driven out by the beer at the valve II, this valve is closed, after the valve ID has been opened. Thus there is no risk of entry of yeast cells into the pipe I and, in the subsequent flow of yeast-free beer, of carrying any yeast into the tank 4.

When using separators provided with so-called paring discs a mode of operation can be as follows (see Figs. 1 and 2):

When the separating has been interrupted and the beer has been driven out by the water then the water feed is interrupted. The valve Ill in pipe 1 leading from the discharge conduit 25 from the centrifuge is shut. When the separator bowl has been stopped the nut 2| is loosened. The paring disc is then pressed downwards by means of the element 22, which, acting through a ring 21 and packing ring 28, forces the parer 29 down until its lower packing ring 24 makes tight contact with the underlying bowl part, as shown in dotted lines in Fig. 2, and the packing ring 30 makes a tight joint at 23. The packing ring 3| makes a tight joint between the ring 21 and the tubular portion 32 of the discharge passage. Then water from pipe 8 and valve II is flushed through the discharge conduit 25 backwards through the bowl and. out through the feed pipe 26. The flushing is interrupted when the water streaming out looks clean. In restarting the centrifuge the nut 2! is again tightened to the position shown in Fig. 2, thereby returning the parer 29, ring 21 and element 22 to the position shown. The valve in the discharge conduit 25 is not opened until the bowl has attained its full speed. Then the valve 9 in the feed pipe is opened for feeding in the normal direction first water and then beer through the bowl.

It will be understood that in Fig. 2 the bowl inlet or feed pipe 26 is connected at the top in any suitable manner to the feed pipe shown in Fig. l, and the discharge conduit is connected to the pipe 1 in Fig. l. The parer 29 is normally in the position shown in Fig. 2, wherein the parer and the bowl outlet 33 are in ,communication with the atmosphere through the open space surrounding the neck of the parer. In this position of the parer, it affords communication between the interior of the centrifugal bowl shown in Fig. 2 and the discharge conduit 25 for the purified liquid, the communication to the bowl interior being to both the central zone (through the space 34 below the parer and surrounding the feed pipe 26) and the peripheral zone (through the passage 35 below the parer). The ring 21 and its packing ring constitute a means operable to close communication between parer 29 and the atmosphere, by downward movement of parts 21, 30 to their dotted line positions (Fig. 2). In other words, the parts 27; 3 together with the parer form means for sealing the bowl outlet 33 (into which the parer extends) from atmosphere while providing a sealed flushing connection between discharge conduit 25 and. the bowl outlet 33. This sealed flushing connection is from the annular space 36 within the stationary tubular portionx32' through the sealing ring 28 and thence through 4 the parer passages 29a, and it is provided independently of the space 34 between the feed pipe 26 and the surrounding bowl portion. Since the parer moves downwardly with ring 21, the lower packing ring 24 on the parer constitutes an element operable by the closing means 21 to close communication between the parer and the central zone of the bowl through space 34. That is, the lower ring 24 forms a means for sealing the space 34 between feed pipe 26 and the surrounding bowl portion, such means being movable between sealing (dotted line) and non-sealing (full line) positions for flushing and normal operation, respectively. With the parts in their lower positions, the flush liquid fed through pipes 8 and 'l' and conduit 25 can pass only through parer 29, passage 35, and the peripheral zone of the bowl, and out through the feed tube 26 and pipe 5 to the discharge duct 6 for the flush liquid.

The element 22 constitutes a means operable selectively to move the sealing means, including the parts 21, 3D and the parer, between the lower or sealing position and the upper or non-sealing position, depending upon whether the bowl interior or locus of centrifugal force is to be flushed or is to be used normally for separating impurities from the liquid.

The described method of cleaning centrifugal bowls is not limited for use in the centrifugal treatment of beer, but is equally applicable to the cleaning of centrifugal bowls when, in the centrifugal purification of any liquid, solids and semi-solids are deposited in the bowl and at intervals require removal by flushing.

What I claim and desire to protect by Letters Patent is:

1. In a centrifuge comprising a centrifugal bowl having walls defining an outlet in communication with the atmosphere, a feed pipe for conducting a liquid into the bowl. there being a clearance space between the feed pipe and the surrounding bowl portion. and means for sealing said space and movable between sealing and nonsealing positions for flushing the bowl and for normal operation of the centrifuge. respectively, the combination of a conduit outside the bowl for communicating with said outlet independently of said clearance space and adapted to receive a bowl flushing liquid, means for sealing said outlet from the atmosphere while providing a sealed flushin connection between the conduit and said outlet inde endently of said space, and means operable selectively to move said last sealing means between sealing and non-sealing positions.

2. A centrifuge as defined in claim 1, in which said last sealin means includes a parer extending into said outlet and normally communicating with the conduit, the parer forming part of said flushing connection in the sealing position of said last sealing means.

3. An insta lation for practicing the herein described process, which comprises a supply tank, a centrifuge having a centrifugal bowl, an inlet to the bowl, a discharge conduit from the bowl, and a parer normally in communication with the atmosphere and affording communication between the'bowl interior and the discharge cond'uit, a supply conduit connecting the supply tank and said centrifuge inlet, a storage tank connected to the discharge conduit, a device in the discharge conduit for closing the same, a duct for admitting a'flushing liquid to the discharge conduit at a region between the bowl and said device} a device in the supply conduit for closing the same, a duct for discharging flush liquid through and out of the supply conduit at a region between the bowl and said last device, and means operable to close communication between the parer and the atmosphere, to direct the flow of flushing liquid from the discharge conduit only through the bowl and thence to the supply con duit and to said dischar e duct.

4. An installation according to claim 2, in which the parer is normally in open communica tion with both the central and the peripheral zones of the bowl, and an element operable by said means to close communication between the parer and the central Zone of the bowl.

TORE VERNER HANNO.

REFERENEES CITED The following references are of record in the file of this patent:

Number Number Certificate of Correction Patent No. 2,502,945 April 4, 1950 TORE VERNER HANNO It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 9, for the claim reference numeral 2 read 3;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 27th day of June, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

